Gold/Atomic mass
196.96657 u ± 0.000004 u
Potassium/Atomic mass
39.0983 u ± 0.0001 u
Francium/Atomic number
87
Copper/Atomic mass
63.546 u ± 0.003 u
Bromine/Atomic mass
79.904 u ± 0.001 u
Arsenic/Atomic number
33
__MgF2 + __Li2CO3 + __ 2LiF
1. b
2.a
3.c
I think . hope I get it right